10. Blood Flashcards
Plasma
non-living fluid matrix,
makes up 55% of blood
90% water
lots of things dissolved in it: nutrients, salts, gases, hormones, plasma proteins, waste products
formed elements
living blood cells
Erythrocytes
red blood cells, transport oxygen
45% of volume of blood sample
-they don’t have a nucleus and many organelles
- are bags of haemoglobin molecules
Buffy coat
in blood sample, layer between plasma and erythrocytes
- contains: leukocytes (white blood cells), platelets
- account for 1% of blood
Platelets
cell fragments that help stop bleeding
Hematocrit
blood fraction, percentage of erythrocytes in blood (45%)
Blood colour
- scarlet - oxygen rich
- dull red to purple - oxygen poor
blood pH
slightly alkaline 7.35 - 7.45
Blood temperature
38deg. slightly higher due to friction against blood vessel walls
Blood amount in humans
8% of body weight or
5-6 litres
Plasma proteins
found in plasma, produced by liver, serve a variety of functions
Albumin
plasma protein, carrier certain molecules, is a blood buffer, contributes to osmotic blood pressure
Fibrogens
clotting proteins found in plasma, help patch up injured blood vessels
e.g. Fibrinogen
Globulins
type of proteins in blood plasma, Defence antibodies and can transport lipids
Haemoglobin
(Hb) iron-bonding protein, transports oxygen in the blood, also binds with a small amount of CO2
If blood pH falls too acidic, haemoglobin will be unable to bind oxygen
12-18g per 100ml of blood
Anaemia
decrease in oxygen-carrying ability
- due to low number of erythrocytes or abnormal haemoglobin content in erythrocytes
Sickle cell anaemia
(SCA) body does not form normal haemoglobin, instead it forms a sharp and spiky shape when oxygen is unloaded or oxygen content in blood decreases below normal
- rupture easily, block small blood vessels
- helps survive malaria
- evident in dark-skinned populations descendant from malaria belt of Africa
- requires 2 copies of defective gene
Sickle cell trait
(SCT) when person only has 1 gene causing sickle cell anaemia
-don’t have symptoms but can pass the gene on
Polycythaemia
excessive increase in number of erythrocytes
-may result from bone marrow cancer (polycythaemia vera) or from living in high-altitude area where there is less oxygen (secondary polycythaemia)
Polycythaemia vera
excessive increase in number of erythrocytes
result from bone marrow cancer
Secondary polycythaemia
excessive increase in number of erythrocytes from living in high-altitude area where there is less oxygen
Haemorrhagic anaemia
decrease in red blood cells due to bleeding out suddenly
Haemolytic anaemia
decrease in red blood cells due to their lysis by bacterial infections
Pernicious anaemia
decrease in red blood cells due to lack of vit B12
Aplastic anaemia
decrease in red blood cells due to destruction of bone marrow by cancer/radiation/medication
Iron-deficiency anaemia
Inadequate haemoglobin content in RBCs due to low amount of iron which is needed in built of haemoglobins
Leukocytes
white blood cells. Defend body against microorganisms and tumour cells. They can move in and out of the bloodstream by diapedesis.
Diapedesis
cells or material that can slip in and out of the blood vessels
Positive chemotaxis
WBCs locate area of tissue damage by responding to chemicals diffusing from damaged cells, then they move through the tissue spaces by amoeboid motion. They follow diffusion gradient they find tissue damage and start destroying microorganisms and dispose of dead cells
Amoeboid motion
WBCs use this. cells form flowing cytoplasmic extensions that help them move along
Leukocytosis
double the normal amount of WBCs. Generally indicates bacterial/viral infection. As leukocytes start defending the body, the body start producing more of them
Leukopenia
abnormally low WBCs caused by some drugs (corticosteroids and anticancer agents)
Leukaemia
excessive production of abnormal WBCs done in infectious mononucleosis. Bone marrow becomes cancerous and huge number of WBCs are expelled rapidly which are immature and incapable of doing their job. Body becomes easy prey with no protection. Because they fill the blood, this leaves little space for rest of blood cells (RBCs) causing anaemia and bleeding problems
Types of WBCs
Granulocytes
Agranulocytes
depending if they have visible granules in their cytoplasm
Granulocytes
WBCs with granules in their cytoplasm which stain with Wright’s stain
3 types:
neutrophils, eosinophils, basophils
Neutrophils
most common WBCs, phagocytes at acute infection. Particularly partial to bacteria and fungi which they kill with a respiratory burst
Respiratory burst
WBCs flood the phagocytised invader with a brew of oxidising substances (bleach, hydrogen peroxide, +)
Phagocyte
a type of cell within the body capable of engulfing and absorbing bacteria and other small cells and particles.
Eosinophils
WBCs which increase in numbers during infections by parasitic worms (tapeworms) via digestion or broken skin. Attack by releasing enzymes form their cytoplasmic granules onto parasite, digesting it
Basophils
rare WBCs, with large granules containing histamine
Histamine
inflammatory chemical that causes blood vessels to be leaky and attract other WBCs to the infection site
Agranulocytes
WBCs which lack visible cytoplasmic granules
types: lymphocytes, monocytes
Lymphocytes
take up residence in lymphatic tissues (tonsils) and play a role in immune response. Second most common WBC.
Monocytes
Largest of WBCs, when they migrate into tissues they change into macrophages which start eating aiding fighting chronic infections and in activating lyphocytes
Macrophages
type of white blood cell, of the immune system, that engulfs and digests cellular debris, foreign substances, microbes, cancer cells, and anything else that does not have the type of proteins specific to healthy body
List WBCs in order of relative abundance in blood
Never Let Monkeys Eat Bananas Neutrophils Lymphocytes Monocytes Eosinophils Basophils
Platelets
fragments of cells with multiple nuclei called megakaryocytes. They pinch off anucleate platelet pieces
Used for blood clotting
Haematopoiesis
blood cell formation in red bone marrow (myeloid tissue). They are released into blood flow. All arise from stem cell hemocytoblast
Hemocytoblast
stem cell in red bone marrow. Produces 2 descendants: lymphoid stem cell and myeloid stem cell
lymphoid stem cell
produces lymphocytes
myeloid stem cell
produces other cell formations for blood except for lymphocytes
Formation of red blood cells
Hemocytoblasts start dividing and synthesising lots of haemoglobin. When enough is made, nucleolus and other organelles are ejected and cells collapse inwards creating the doughnut Erythrocyte cell. during first few days of cell’s life it still has some endoplasmic reticulum and is called Reticulocyte.
Reticulocyte
when erythrocyte cell is created it still has some endoplasmic reticulum for few days before it becomes fully ejected
Erythropoietin
hormone controlling rate of erythrocyte production. small amounts circulate in the blood. Produced by Kidneys and some by liver. Production increases when the amount of oxygen drops in the blood
Colony stimulating factors (CSFs) and Interleukins
hormones activating production of white blood cells by prompting red bone marrow to produce more and enhancing abilities of old leukocytes
Thrombopoietin
hormone accelerates production of platelets from megakaryocytes
Haemostasis
stopping the bleeding Phases: -Vascular spasms - Platelet plug formation - Coagulation - Blood clotting
Haemostasis: vascular spasms
vasoconstriction as response to tear in blood vessel wall
Haemostasis: platelet plug formation
platelets start clinging to collagen fibres sticking out of torn wall. They then release chemicals enhancing vascular spasms and enhancing more platelets
Haemostasis: Coagulation
Tissue releases TISSUE FACTOR which interacts with PLATELET FACTOR 3 (PF3, on platelet surface) and CALCIUM IONS and others forming an activator leading to formation of THROMBIN (enzyme) which joins FIBINOGEN proteins AND FORMS long molecules FIBRIN. Fibrin forms mesh that traps RBCs and forms basis of clot. After an hour clot retracts. squeezing SERUM (plasma minus proteins) from the mass and pulling edges together
Thrombus
blood clot that develops and persists on unbroken blood vessel. Might be large enough to prevent blood flor
Pulmonary thrombus
Blood clot blockage (thrombus) in the blood vessels serving lungs with possible outcome as death of lung tissue
Hypoxia
inadequate oxygen delivery to body tissue resulting in tissue death
Embolus
Thrombus blood clot that broke away and is freely floating until it lodges in a small vessel blocking the flow
Cerebral embolus
Embolus (floating thrombus blood clot) which floated to brain and blocked a blood vessel causing stroke and brain tissue death
Possible thrombus causes
Severe burns Physical blows Accumulation of fatty material Slow blood flow Blood pooling in immobilised patients
Anticoagulants
anti-clotting medicines: aspirin, heparin, warfarin
Thrombocytopenia
platelet deficiency, causing abnormal bleeding. might result from impaired liver or genetic condition, bone marrow cancer, radiation, drugs
Petechiae
small purplish blotches on skin (resembling rash) caused by bleeding disorder thrombocytopenia - reflects small bleeds in body as result of normal movements
Haemophilia
several hereditary bleeding disorders
Loss of blood in %
15-30% loss causes paleness and weakness
over 30% loss causes severe shock which can be fatal
Antigen
substance body recognises as foreign and stimulates immune system to fight it
Antibodies
present in plasma, attach to RBCs with surface antigens different to those on own RBCs
Agglutination
binding of antibodies in blood causes foreign RBCs to clump and clog small blood vessels. The foreign RBCs and then ruptured. Released Haemoglobin could block kidney tubules causing kidney failure (treatment by diuretics)
Rh blood groups
Rh antigens in blood cells (-) or (+) for purposes of blood transfusion
Haemolytic disease of the new-born
When mother goes through second pregnancy where baby has a different Rh blood antigen. Her antibodies will destroy baby’s RBCs - anaemic, hypoxic, cyanotic. Can lead to brain damage and even death (treatment: foetal transfusions)
Jaundice
term used to describe a yellowish tinge to the skin and the whites of the eye. Body fluids may also be yellow. The colour of the skin and whites of the eyes will vary depending on levels of bilirubin. Bilirubin is a waste material found in the blood.
Intrinsic factor
produced by stomach mucosa, required to absorb vit B12. Lack of it can lead to Pernicious anaemia.
